Insulator



April 9, 1935.

J. J. TAYLOR INSULATOR Filed March 20, 1934 INVENTOR Job/7 J Tay/0r @/.gzx MQ ATTORN Patented Apr. 9, 1935 UNITED STATES PATENT GFFECE INSULATOR poration of New Jersey Application March 20, 1934, Serial No. 716,476

9 Claims.

This invention relates to electrical insulators and particularly to insulators subjected to relatively high bending moments such as pin type, post and pillar insulators.

One object of the invention is to provide an insulator in which relative movement of the parts, due to differential expansion or contraction will take place in the direction of the bearing surfaces of the parts and not transverse to such surfaces, so as to avoid stresses in the connected parts.

Another object of the invention is to provide an insulator inV which the bearing surfaces of the connected parts are advantageously disposed for resisting bending moments.

A further object of the invention is to provide a device of the class named which shall be of iinprovedconstruction and operation.

Other objects and advantages will appear from the following description.

The invention is exemplified by the combination and arrangement of parts shown in the accompanying drawing and described in the following specication, and it is more particularly pointed out in the appended claims.

In the drawing the figure is a vertical sectional view of an insulator showing one embodiment of the present invention.

Electrical insulators are usually made up of metal and dielectric parts connected together by a binding material such as cement. Porcelain is extensively used as a dielectric material andsince the coeiiieient of expansion of porcelain for temperature changes is different from that of most metals, changes of temperature cause differential expansion and contraction of the parts; and unless the insulator is properly designed to accommodate such differential expansion and contraction, stresses are apt to be set up in the porcelain which may produce cracking, since porcelain is a fragile material.

In the present invention the bearing surfaces between the connected parts are so disposed that relative movement takes place along the surfaces rather than transverse thereto, thus avoiding stresses due to expansion and contraction. The arrangement of the surfaces is particularly advantageous in insulators subjected to bending moments.

In the drawing the numeral IB designates a supporting pin for an insulator, on which is mounted a dielectric member I I, which may be of porcelain and to which a metal cap I2 is secured. Cement I3 and I4 is used for connecting the porcelain member to the respective fittings. The

(Cl. 17E- 318) pin it is provided with a plurality of conical bearing faces i5, I6, il and i8 which engage the cement I 3. All the other faces of the pin in contact with the cement are relieved by a coating ES which may be oi some form of compressible material, such as cork, or material which will exclude the cement and afterwards shrink in drying, such as paste. Any coating which will relieve the surfaces of pressure and is otherwise satisfactory may be used.

The upper end of the pin may be closed by a plaster block 23 to prevent entrance of the cement into the interior of the pin. The cap is also provided with a plurality of conical bearing faces 22, 23 and 2li, and the other surfaces of the cap contacting with the cement are relieved in a manner similar to the surfaces i of the pin. All of the bearing surfaces on the cap and pin have a common apex at a point 25 on the axis of the insulator and centrally disposed vertically relative to the bearing faces.

Expansion or contraction of the cap and pin may be regarded as taking place along lines radiating from the point 25 and any expansion of either the cap or pin along these surfaces will be in the direction of the surface of Contact with the cement and not transverse to these bearing surfaces. Relative movement between the fittings and the cement on other surfaces of the fittings will not produce pressure since all of the other surfaces are relieved. It will thus be seen that any expansion or contraction of the metal fittings may be accommodated by relative movement of the bearing surfaces in the direction of these surfaces and that there will therefore be no pressure set up at any bearing surface through such expansion or contraction; and since all the other surfaces are relieved, the entire dinerential expansion or contraction of the parts will be accommodated without setting up stresses in the connected parts.

The bearing surfaces are also advantageously arranged for opposing bending moments. If a bending moment tends to produce relative rotation of the parts about the point 25, the pressure produced between the contacting surfaces will all be normal to these surfaces due to the radial relation of the bearing surfaces to the fulcrum point Eo. Of course, if the fulcruln point is above or below the point 25, the bearing surf aces will not be exactly normal to the forces imposed upon them but nevertheless they will be approximately normal to the pressure so that the surfaces are advantageously disposed to oppose bending moments to which the insulator is subjected.

I claim;

l. An insulator comprising a dielectric member having a recess therein, a pin disposed in said recess, a cap surrounding a portion of said dielectric member and cement connecting said dielectric member with said pin and cap, said pin and cap each having a plurality of oppositely directed spaced bearing faces, all of which bearing faces radiate from a common point.

2. An insulator comprising a dielectric member having a recess therein, a pin disposed in said recess, a cap enclosing the portion of said dielectric member surrounding said recess, cement connecting said dielectric member with said cap and pin, said cap and pin beingdisposed in' overlap-V ping relation, said cap and pin each having spaced oppositely directing bearing faces, the bearing faces of said pin and cap radiating from a com,-V mon point on the axis of said pin, the other surfaces of said pin and cap in contact with the cement and not radiating from said common point being relievedV to prevent pressure between the cement and said pin and cap on said relieved faces. v

3,. An insulator comprising connected parts subject to differential expansion and contraction, saidV parts having cooperating bearing surfaces formed by surfaces of frustums opposed in direction and having a commonapex, adjacent surfaces of said parts other than the surfaces of said frustums having clearance therebetween to restrict the bearing between said parts to the surfaces of said frustums.

e. An insulator comprising connected parts y subject to differential expansion and contraction, one of said'parts being disposed in a recess inthe other, 'said-parts having cooperating bearingv surfaces forming surfaces of opposed frustums having a common apex, said' parts having surfaces connecting Vthe surfaces of said frustums, said connecting surfaces having clearance therebetween to prevent bearing Contact between said connecting surfaces.

5. An insulator comprising a dielectric Vmemberr and aV metal member subject to differential expansion and contraction, one 'of said members extending'into a recess in theother, said'members having cooperating bearing surfaces forming surfaces ofoppcsed frustumshavingv a common apex, adjacent surfaces of said respective parts other than 'the surfaces off said frustums having clearancejtherebetween and thecooperating bear'- ing surfacesfof said frustums. beingl unbonded to each other;

6. An insulator comprising a dielectric member, a metal fitting for said dielectric member, said dielectric member Vand fitting being subject to differential expansion and contraction, said fitting having bearing surfaces thereon forming surfaces of opposed frustums having a common apex, cement interposed between said dielectric member and fitting and providing bearing surfaces conforming to the surfaces of the frusturns on said fitting Vbut being unbonded to said surfaces, adjacent surfaces of said tting and cement other thanthe surfaces of said frustums havingV clearance to restrict the bearing between said fitting and cement to the surfaces of said frustums.

insulator comprising a dielectric mem bei and a metal tting, one of which extends into a recess in the other, said metal tting having conical bearing surfaces thereon forming surfaces of opposed frustmns having a common apex, cement interposed between said dielectric member and fitting and conforming toE the conical bearing surfaces on said Vfitting but being unbonded thereto, adjacent surfaces of said fitting and cement other than the surfaces of said conical frustums having clearance therebetween to restrict the bearing between said dielectric meine ber andtting to said conicalfrustums. v

8. An insulator comprising a dielectric member having a recess therein, a metal pin extending into said recess and differentially expansible and contractible relative to. said dielectric member, said pin having conical bearing surfacesA thereon forming surfaces ofV opposed frustums havingY av common apex, said dielectric member having bearing surfaces thereonv conforming toand cooperating with the surfacesof said frustums, the surfaces of said frustums constitutingthe entire bearing connection between said pin and, dielec tric member.

V9. An insulator comprising a dielectric member having aV recess therein, a. pin extendingA into said recess and having conical bearing, surfaces thereon formingy opposed frustums havingrfaV comv mon apex, cement interposed betweenfsaidpinand, dielectric membelandfenformns will@ bearing surfaces of said frustums j on said pin but being unbonded thereto, adjacent; surfaces of,A said pin and cement other than the Surfaces. 0I; said frusturns having clearance therebetween tore-A Strict the, bearing betweerly SaidY sin and, Cement to saidV conical` frustums, 

